IN THE STUDIO    I    BRET OVERTURF, ARTSIST BIO    I    THE LOST WAX PROCESS

 

THE LOST WAX PROCESS

History

In the third millennium B.C., somewhere between the Black Sea and Persian Gulf, an artist crafted a vision in beeswax, covered it in liquid clay and cooked it in a fire. In the flames the wax was lost, replaced by empty space. Tin and copper - alloys of bronze - were gathered and heated. Once melted, the metal was poured into the cavity of the fire hardened clay. The metal cooled and the sculptor knocked the clay from the metal. The first bronze was cast.

Ancient "Lost Wax" bronze castings have withstood the centuries, visually telling the tale of past cultures, their religion and their social structures. Elements of the "Lost Wax" process have been refined. Yet today, bronze casting is essentially the same as it was in 2,000 BC.

Modern sculptors who want their pieces cast in bronze depend upon a foundry. There, artisans skillfully apply the "Lost Wax" method to wood, stone, clay, plaster or any other kind of sculpture to transform it into bronze. Caleco Foundry, in Cody, WY, is a nationally renowned foundry that casts Bret Overturf's work..

How The Lost Wax Process Works

Original Sculpture
The first step begins by creating an original sculpture. Large pieces are usually created from clay, smaller pieces from wax.

Rubber Mold
Because this is the "lost wax" casting process, a mold must be made from the original. This is done by covering the original with several layers of silicone. This flexible mold captures every detail of the original, and is one of the most critical phases in the bronze process. Depending on the size and complexity of the original, it is often cut into specific pieces. The mold is then covered with a multi layered plaster jacket to keep its shape.

The Wax Casting
The molds are then used to form wax figures: molten wax is poured into the rubber mold. A series of layers of wax are poured into the mold and "slushed" into all the little spaces in the mold. When the wax is cooled, the rubber mold is pulled away from the wax. The wax duplicate is removed from the mold, and a trained artisan hand finishes the wax pattern to the original. Each wax casting is treated as if it were an original work of art.

Sprung
Wax rods, called gates, are attached to the wax pattern to allow the even flow of molten metal and to alleviate the trapping of air and gas.

Ceramic Shell
The ceramic shell is one of the few materials that can stand the heat of molten bronze. Several layers are applied creating a stable mold which is allowed to cure for several days. When the shell is cured, the shell is fired in a kiln. This bakes the shell and eliminates the wax, leaving a cavity in its place.

Casting
After being heated in a kiln, the molten bronze is poured into the form, at a temperature of approximately 2100F.

Breakout
After cooling, the ceramic shell is carefully broken away, revealing a rough casting. Sprues will be cut off and extensive sand blasting will be done in order to prepare it for welding back together. Then by grinding, chasing, sanding and polishing, all areas are blended back together while preserving the integrity of the original.

Fabricating
If there are any details that are too small to cast, the talented fabricator then takes over. Things such as ropes, reins, and the many fine attachments, are then created by hand to the original.

Patina
The chased bronze is now treated with chemicals and heat to give it the chosen colors according to the artist’s specifications. The patina is sealed under a wax coating and becomes a permanent part of the sculpture.

Editions
The piece is stamped with the number and the edition and is now complete. Every individual sculpture I create goes through this extensive process. No step will be hurried. Each finished bronze is a culmination of time, from 3 weeks to 3 months.. The final sculpture is only as good as the time and effort put into it by both myself and the artisans at Caleco Foundry.

 

Info@BretOverturf.com  BretOverturf.com  P: 307. 272.6994  F: 360.285.1801  POB 923, Cody, WY 82414  © 2005 Wildlife Studio  © Design 2005 SageBrush Studios
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